This paper deals with the impact of the use of daylight on the overall energy demand for heating, cooling, and lighting in educational buildings. The energy performance of buildings is currently of the utmost importance as current European regulations, starting from 31st December 2020 impose that all new buildings must meet nearly zero-energy building requirements. This paper presents a study of the illuminance distribution in an educational room obtained from measurements and simulation results using two different models. One of the models, integrated with a thermal simulation software, was used to estimate the impact of daylight on the energy demand. The analysis included the use of various window types, lighting control system, reference point location, and daylight calculation model for a sample room in an educational building. Results of the analysis indicate that, due to the high share of lighting demand (reaching up to 78% of the primary energy balance), there is a need to take into account the efficiency of lighting systems during the design process to correctly determine the actual energy balance of a building, increase the quality of the design of lighting systems, as well as to select the optimal parameters of windows.

The decarbonisation goal stated in the Energy Performance of Buildings Directive (EPBD) regarding the building sector will be achieved only if the whole building life-cycle is considered. To fulfil this requirement, a benchmark based on the life cycle assessment (LCA) must be integrated into the early planning phase of buildings by designers. The estimation of such indicators requires the development of a database of building assessments. In this study, an LCA of 11 office buildings in Poland was used to set average values that can be used as a benchmark. The LCA methodology based on the Building Research Establishment Environmental Assessment Method (BREEAM) certification was used. The analysis did not concentrate on one type of office building. The main objective was to investigate a possible range of total Global Warming Potential (GWP) index values normalized to the usable unit floor area. The importance of the GWP of individual life-cycle phases was also considered. The study shows that the used methodology is adequate for LCA benchmark estimation to set preliminary average values for office buildings in Poland.

The need to achieve energy consumption and greenhouse gas emission decreases within the building sector requires the implementation of a supportive legal framework. To fulfil this requirement, a building certification system must be developed that is easily understandable for end users. In Poland, assessments of the energy performance of buildings are based on primary energy indicator verification. However, this parameter is difficult to understand for building owners or for tenants. Therefore, in this study, energy efficiency class limits and a heating indicator for energy needs indicator have been estimated for multi-family buildings in Poland. To achieve this purpose, a reference building was used and 180 calculation variants were developed, which considered the following variables: 3 types of climate data, 4 values of building shape ratios, 3 types of ventilation, 3 thermal transmittance standards and 3 windows area ratios to the external wall. The results showed that the greatest influences on the need for energy used for heating were the type of ventilation used and the local climate. This study shows that the methodology used is adequate for energy efficiency class limits estimations involving multi-family buildings in Poland.

This paper presents the results of comparative analysis of energy and environmental life cycle assessment of a building envelope with different WWR. The analysis is simplified to: product stage and use stage as the main sources of GHG emissions. Embodied and operational CO2 equivalent were evaluated for two typical office buildings located in Poland with different wall to floor ratio. Carbon footprint of the use stage, associated with the energy consumption, was calculated according to polish energy fuel mix.The maximum emission of CO2eq occurred for the scenario with glass curtain wall and it decreased along with reduced window area

Lowering energy consumption is one of the most important challenges of the modern world. Since the construction sector accounts for 40% of total energy consumption worldwide, the Parliament of the European Union has developed a Directive, according to which all newly designed and thermally upgraded buildings should meet the requirements of almost zero energy demand (nZEBs) from 1 January 2021. At the same time, in Poland, but also in many other countries in the world, there is a growing oversupply of office space in large cities with a simultaneous increase in demand for apartments, which is caused, among other things, by the increase in the share of remote work and the COVID-19 pandemic. Consequently, this is forcing owners to change the use of buildings from office to residential. This article analyses the possibilities of changing the function of an office building to a multi-family residential building. For both functional solutions, a comparative energy analysis was carried out, taking into account different work schedules and the requirements for new buildings with zero energy demand. The analyses have shown that changing the form of use of an office building to a multi-family building without significant financial and technical costs is possible. On the other hand, the reverse change of the form of use is much more difficult and, in many cases, practically impossible. Due to the fact that many offices are now multinational corporations, this issue is global.